Investments (Securities Lending) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Securities Financing Transaction [Line Items]
Total cash collateral liability	$ 7,108	$ 7,502
Security collateral on deposit from counterparties	5	51
Reinvestment portfolio - estimated fair value	7,123	7,533
Securities Financing Transaction, Cost [Member]
Securities Financing Transaction [Line Items]
Securities loaned	6,695	6,154
Securities Financing Transaction, Fair Value [Member]
Securities Financing Transaction [Line Items]
Securities loaned	$ 6,959	$ 7,339

This element represents the estimated fair value of the securities lending reinvestment portfolio.

No definition available.

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- Details

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- Definition

Amount, after the effects of master netting arrangements, of securities loaned to entities in exchange for collateral. Includes liabilities not subject to a master netting arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (c)

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

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-Section 55

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=28370219&loc=SL20226008-175313

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-Publisher FASB

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 940

-SubTopic 405

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+ Details

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- Definition

The carrying value as of the balance sheet date of the assets received as collateral against securities loaned to other broker-dealers. Borrowers of securities generally are required to provide collateral to the lenders of securities, commonly cash but sometimes other securities or standby letters of credit, with a value slightly higher than that of the securities borrowed. In instances where the entity is permitted to sell or re-pledge these securities, the entity reports the fair value of the collateral received and the related obligation to return the collateral as a liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 30

-Section 50

-Paragraph 1A

-Subparagraph (b)(1)

-URI http://asc.fasb.org/extlink&oid=7523297&loc=SL6224234-111729

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-Publisher FASB

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-Topic 860

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-URI http://asc.fasb.org/extlink&oid=7517284&loc=d3e93645-111703

+ Details

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- Definition

Carrying amount of liabilities associated with financial assets accounted for as secured borrowings recognized in the transferor's statement of financial position at the end of each period presented.

+ References

+ Details

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